The eye includes several tissues that allow patients to see. The cornea of the eye is an anterior tissue of the eye that is clear in healthy eyes and refracts light so as to form an image on the retina. The retina is a posterior tissue of the eye that senses light from the image formed thereon and transmits signals from the image to the brain. The cornea includes an outer layer of tissue, the epithelium, which protects the underlying tissues of the cornea, such as Bowman's membrane, the stroma and nerve fibers that extend into the stroma and Bowman's membrane. The healthy eye includes a tear film disposed over the epithelium. The tear film can smooth small irregularities of the epithelium so as to provide an optically smooth surface. The tear film is shaped substantially by the shape of the underlying epithelium, stroma, and Bowman's membrane, if present. The tear film comprises a liquid that is mostly water and does include additional components, such as mucoids and lipids. The many nerve fibers of the cornea provide sensation to promote blinking that can cover the cornea with the tear film. The nerve fibers also sense pain so that one will normally avoid trauma to the cornea and also avoid direct contact of an object to the cornea so as to protect this important tissue.
Refractive eye surgery is used to improve the refractive state of the eye and includes procedures such as, for example, automated lamellar keratoplasty (ALK), laser assisted in-situ keratomileusis (LASIK), photorefractive keratectomy (PRK), laser assisted sub-epithelium keratomeleusis (LASEK), EPI-LASIK, radial keratotomy, mini-asymmetric radial keratotomy, arcuate kertotomy, limbal relaxing incisions, thermal keratoplasty, laser thermal keratoplasty, intrastomal corneal ring segment removal, and phakic intraocular lens implantation. Following any of these procedures there is a period of time before optimal vision is restored. For example, in LASIK, optimal vision is typically achieved within about 24 hours following surgery. During this recovery period, in addition to sub-optimal visual acuity, a patient may experience discomforts such as photophobia or light sensitivity and/or a burning sensation. Methods for reducing the time to achieve optimal vision and for reducing or eliminating discomfort associated with refractive eye surgery are desired.